Injector-ram jet engine



June 2, 1970 w. R. BRAY INJECTOR-RAM JET ENGIN Filed March ll, 1968 United States Patent O 3,514,956 INJECTOR-RAM JET ENGINE William R. Bray, 610 Memorial Drive, Fort Walton Beach, Fla. 32548 Filed Mar. 11, 1968, Ser. No. 712,279 Int. Cl. F02k 7/10 U.S. Cl. 60-269 4 Claims ABSTRACT OF THE DISCLOSURE A plurality of divergent nozzles are mounted in a continuous line and in overlapping relation to each other in the main nozzle passage of a ram jet engine tube having main air intake and exhaust openings. These divergent nozzles are of increasing size and greater divergency in the downstream direction and each includes an inlet opening section sufficiently enlarged both to accommodate the insertion therewithin of the exhaust opening section of the nozzle positioned next upstream thereof, and to receive a primary fuel-air mixture produced in said passage by the inducement therein of a primary supply of air admitted through the main air intake and its subsequent mixture with fuel. The last divergent nozzle terminates in an exhaust opening section coinciding with the main exhaust opening. A unique engine self-starter tube is mounted to the main tube just downstream of the main air intake, and it includes an auxiliary divergent nozzle tube section that projects into the inlet opening section of the divergent nozzle positioned in the main passage nearest the main air intake, and an auxiliary compressed air supply tube section for supplying compressed air for mixture with fuel in the first-named section to thereby produce an auxiliary fuel-air mixture. A spark plug is mounted in the nozzle tube section for igniting this fuel-air mixture and exhausting the products of combustion resulting therefrom into the divergent nozzle located nearest the main air intake. The exhausting products of combustion induce a primary fuel-air mixture into the enlarged inlet opening section of the first divergent nozzle, which fuel-air mixture is immediately ignited by the initially formed products of combustion in the selfstarter tube and is thereafter accelerated downstream at ever-increasing velocities to thereby produce an increasingly larger-and-larger thrust.

BACKGROUND OF THE INVENTION This invention relates generally to the field of ram jet engines and, in particular, to a ram jet engine modified to have a self-start capability at zero velocity.

By definition, the usual ram jet engine is a streamlined tube having a single continuous nozzzle open at both ends. For this reason, the ram jet engine normally has no self-starting capability, since if fuel Were injected therein while the tube was stationary and then ignited, the resulting products of combustion would be expelled out both the inlet and exhaust ends of the ram jet engine tube. As a result, the use of the ram jet engine for highspeed flight has been investigated principally from the viewpoint of its combination with some other type of jet engine, as for example, the turbojet, or, alternatively, as a combined turbo-ramjet wherein the same inlet, combustor, and nozzle are used for both the turbojet and ram jet operation phases. However, the present invention consists of a ram jet engine that is modified to provide the previously-noted lack of a self-start capability in a specific manner to be further discussed in the following summary and description thereof and, as such, is considered an appropriate vehicle for use in the continued research and development into advanced propulsion concepts involving flights at supersonic and hypersonic speeds and at altitudes up to and including the extremely high altitudes involved in orbital flights.

SUMMARY OF THE INVENTION The principal object of the present invention, therefore, is \in a new ram jet engine having an improved main, openended tube and nozzle arrangement in novel combination with a unique self-starter device for initially forming and igniting an auxiliary fuel-air mixture therein and thereafter accelerating and exhausting the products of combustion resulting therefrom rearwardly at a relatively high velocity into the main tube and nozzzle arrangement for its further acceleration therein.

A further object of the invention resides in a novel ram jet engine tube and self-starter device combination that includes a series of separate but overlapping and continuous `divergent nozzles mounted within, and dividing the tube into a corresponding number of nozzle operational stages respectively adapted to progressively accelerate products of combustion being exhausted from the self-starter device to ever-increasing velocities in a rearward direction for the final ejection thereof from the main ram jet engine tube exhaust opening.

A still further object of the invention is in an improved main ram jet engine tube incorporating a novel selfstarter device in unique combination with a series of divergent nozzles located in the main engine tube in respective communication with the main tube air intake opening, each adjacently positioned nozzle, and the selfstarter tube to thereby ensure an increasingly large primary gas fiow and the acceleration thereof from the main tube into the series of divergent nozzles as a result of being induced thereinto by the products of combustion initially formed in said self-starter tube and subsequently exhausted into said divergent nozzles.

Other objects and advantages of the invention will become readily apparent from the following disclosure, and accompanying claims, in which the single figure of the drawing represents a partly schematic and longitudinal sectional view of the improved configuration ram jet engine of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the single figure of the drawing, the present ram jet engine is shown generally at 10 as including a main engine tube 11 having a main nozzle passageway 12, a main inlet,or air intake 13 and a main exhaust opening at 14. The tube 11 and, in particular, the aforesaid main nozzle passageway 12 is modified for improved operation by being oriented or divided into three stages of operation, the first stage being indicated at 15, the second stage at 16, and the third stage at 17. The foregoing three stages are the result of an improved nozzle arrangement involving the mounting in the main nozzle passageway 11 of three separate divergent nozzles, indicated by the rst, second and third stage nozzles respectively shown at 18, 19 and 20. These nozzles are positioned so that the exhaust opening ends 18b and 19b, respectively, of the first and second stage nozzles 18 and 19 are inserted within the inlet or intake openings of the next succeeding stages corresponding thereto, as is clearly illustrated at 19a and 20a in the drawing. The third stage nozzle 20 terminates in an exhaust opening end that coincides with, and may be formed integral to the main exhaust opening 14. Moreover, the nozzle inlets or intake openings, as shown at 18a, 19a and 20a, respectively, are sufiiciently enlarged in diameter both to ensure adequate space for the insertion therein of the previously-referred to nozzle-exhaust openings 18b and 19b, and, in addition, to provide for one of the key operational features 3 of the present invention; namely, the accommodation of a primary fuel-air mixture that is uniquely induced .into the inlets 18a, 19a and 20a of said nozzles 18, 19 and 20 in their respective turn during the overall operation of the present ram jet engine in a specific and improved manner to be described hereinafter in detail. In this regard, to ensure the capture of the entire gas flow and its subsequent exhaust from the main exhaust opening 14, the inlet 20a of the third or last stage nozzle 20` is enlarged as shown to the same diameter as is the main tube 11 and, accordingly, the entre gas fiow is then required to pass through the aforesaid third stage nozzle 20 for exhaustion from the said main exhaust opening.

The ram jet engine of the present invention is further modified in a unique and improved manner by the addition thereto of a novel engine self-starter tube indicated generally at 21, which starter tube 21 is adaptable to be mounted near the front of the main engine tube 11, or, in other words, nearly adjacent to the main air intake 13. Self-starter tube 21 includes a first tube portion at 21a that extends outside of the main engine tube 11 and may be suitably interconnected in any appropriate manner to a central compressor unit, which may, for example, be mounted to the fuselage of a multijet aircraft and suitably interconnected from a common air supply line to the ram jet engine incorporating the present invention. This connection would be at the aforesaid first tube portion 21a. However, this common compressor unit and its specific interconnection is not illustrated since the specific nature thereof is only generally related to the specific construction of the present invention. The previouslyreferred to first tube portion 21a, therefore, constitutes a compressed air supply tube section that is adapted to be integrally joined with a second, engine self-starter tubedivergent nozzle section at 2lb, the purpose of which and its operation will be described hereinafter in detail.

The present engine may be uniquely started while the tube 11 is in a stationary position by initially admitting compressed air thereinto from a suitable source of compressed air supply, such as the central compressor indicated above, by way of the starter turbe-compressed air supply tube section 21a', which compressed air thereafter ows into the inlet or intake, indicated at 21C, of the starter tube-divergent nozzle section 2lb, at which point an appropriate amount of fuel, such as hydrogen, may be intermixed therewith by use of any appropriately designed fuel nozzles, such as that illustrated schematically at 22 located adjacent to the inlet 21e. As the fuel-air mixture formed thereby continues to iiow downstream in the aforesaid starter tube-divergent nozzle section 2lb*I it is subsequently ignited `by a spark plug, such as that shown in schematic form at 23. From this ignition point, and by appropriately configuring the said starter-tubedivergent nozzle section 2lb, the already relatively fastmoving products of combustion resulting from said ignition may thereafter :be accelerated to, and exhausted from the nozzle exhaust opening section, indicated at 21d, at supersonic velocities for the subsequent entry thereof into the aforesaid inlet or intake opening 18a of the first stage divergent nozzle 18. This rapid exhaustion of the products of combustion initially formed in the self-starter tube 21 and their entry into the inlet of the nozzle 18 results in inducing a primary flow of air through the main air intake 13. Hydrogen fuel adapted to be supplied for intermixture therewith, as `by means of the first stage fuel nozzles shown schematically at 24 as positioned in passageway 12 just upstream of the first stage nozzle 18, is likewise induced by the previouslydescribed exhausting products of combustion from selfstarter tube 21 to thereby form a primary fuel-air mixture that is thereafter induced into injection in the enlarged inlet 18a of said first stage nozzle 18. At this time, the products of combustion being exhausted from said self-starter tube 21 intermix with, and ignite the said primary fuel-air mixture to thereby form additional prodthe' latter was initially in a stationary condition. In this connection, the principle of operation involved at this point is based on the consideration that a pumping action actually occurs at the entry into the mouth of the inlet 18a. This pumping action is, in effect, the result of the combined and cumulative action of the initially formed products of combustion Ibeing exhausted from the selfstarter tube 21 and the inducement thereby of the primary fuel-air mixture from the passageway 12. When coupled with the fact that immediately upon entry of this fuel-air mixture into the mouth of the inlet 18a through the inducing effect of the said initially formed products of combustion, the said mixture is compressed and then ignited, it is obvious that a further and significantly larger acceleration is applied to the products of combustion and a pumping effect is the result. Therefore, the mouth of the inlet 18a becomes in effect a first stage injector. Naturally, since the previously-formed products of combustion exhausted from the self-starter tube 21 are already moving in a rearward or downstream direction and, likewise, the fuel-air mixture induced into the first stage nozzle 18 is initially moving in the same downstream direction, the products of combustion subsequently formed therefrom will likewise continue to accelerate rearwardly because of the unbalanced forces inherent in such arrangement. The forces due to the aforesaid acceleration are naturally determinable from the product of the mass of the products of combustion times the acceleration applied thereto, and, conversely, the reaction force or thrust developed therefrom is equal and opposite thereto.

As the above-described products of combustion formed in the first stage nozzle 18 are expelled or exhausted therefrom in a downstream direction and at an increasing acceleration, they are in turn injected into the mouth or inlet 19a or the second stage nozzle 19, at which point, additional air, now owing through air intake 13 and in the passageway 12 at an increasing rate as a result of the above-described operation of the first stage nozzle 18, is induced as before into the mouth or inlet 19a of the said second stage nozzle 19. Again, fuel is intermixed with the said air as by means of the second stage fuel nozzles indicated schematically at 25 and the combined fuel-air mixture is further induced into the aforesaid inlet 19a and immediately thereafter ignited, again, by the products of combustion being exhausted from its first stage nozzleexhaust opening 18b. Once again, these products of combustion are accelerated rearwardly at an ever-increasing velocity and are then exhausted from the second stage nozzle-exhaust opening 19b into the mouth of the inlet 20a of the third stage nozzle 20. This latter action likewise induces a still greater flow of air through the passageway 12, intermixed with appropriate amounts of hydrogen fuel by means of the third stage fuel nozzles shown schematically at 26. The third stage fuel-air mixture formed therefrom and almost immediately thereafter injected into the inlet 20a of the third stage nozzle 20 through the inducing effect of the cambined products of combustion of the first and second stage nozzles 18, 19 being exhausted thereinto are ignited as before to form new products of combustion which added to the previously-formed products of combustion combine together for acceleration 'through the third stage nozzle 20 to thereby result in the production of a combined thrust resulting from the action of all three divergent nozzles. Of course, once the ram air pressure became sufficient in itself as when reaching cruising speed to operate the present ram jet engine, then, the compressed air supply to the selfstarter tube 21 could be shut-off from the central compresser unit by any suitable valve means, and ordinary ram jet operation begun.

What is claimed is:

1. In a modilied ram jet engine; a main engine tube having a main nozzle passageway with main, air mtake and exhaust openings, and at least one primary fuel-1npection means; primary nozzle means interposed in said passageway between said main air intake andmaln exhaust openings, said primary nozzle means having a nozzle-exhaust opening coinciding with said maln exhaust opening and at least one primary nozzle-inlet means positioned with its mouth in said maln nozzle passageway immediately downstream of said primary fuel-injection means and being further relatively enlarged to facilitate open communication with said main, air intake openlng; and an engine self-starter device mounted to said main engine tube adjacent the upstream end thereof and 1n open communication with the inlet means of said pr1- mary nozzle means and adapted to start initial combustion in said engine tube and thereby initiate the production of thrust therein 'while said main engine tube is at rest, said self-starter device having a lirst, compressed arr supply tube portion for delivering an initial, auxiliary supply of compressed air to said engine self-starter device, and a second, gas flow-delivering means integrally joined and having inlet means communicating with, and receiving said initial supply of compressed air from sald iirst, compressed air supply tube portion, said second, gas flow-delivering means further having an auxiliary exhaust opening portion inserted Within the inlet means of said primary nozzle means, and auxiliary fuel injection and ignition means positioned respectively at, and downstream of said flow-delivering inlet means for initially intermixing auxiliary fuel with said supply of compressed air being received from said tube portion and thereby forming an auxiliary fuel-air mixture therewith, and subsequently igniting said fuel-air mixture to thus form initial products of combustion for exhaustion at relatively high velocity from said gas flow-delivering means out of said auxiliary exhaust opening thereof directly into the inlet means of said primary nozzle means, said initially formed, exhausting products of combustion thereby simultaneously inducing a ilow of primary air through said main air intake opening, and a supply of primary fuel from said primary fuel injection means for intermixing with said primary air to thereby form a primary fuel-air mixture for injection immediately thereafter into the inlet means of said primary nozzle means by the inducing action of said initially formed, products of combustion being exhausted from said self-starter device, said primary fuel-air mixture being immediately thereafter ignited and accelerated by, and in concert with said initially formed products of combustion to thereby produce initial thrust in said main engine tube while the latter is at rest, said primary nozzle means being operably associated with a series of primary fuelinjection means located at progressively-further downstream positions in said main nozzle passageway, and further comprising a plurality of individual, axially-aligned nozzle portions of increasing divergency in the downstream direction, and being further arranged with integrally formed inlet and exhaust opening portions positioned in overlapping relation to each other, with a respective inlet opening portion immediately downstream of a primary fuel-injection means corresponding thereto, said inlet opening portions being progressively enlarged in the downstream direction and in open communication with the main nozzle passageway and main air intake opening to thereby provide for the progressive induction of larger-and-larger amounts of primary air for initial inter-mixture lwith additional primary fuel induced at progressively-further downstream locations -in said passageway from a corresponding primary fuel injection means, each of the primary fuel-air mixtures being thereby formed in said main nozzle passageway being respectively induced into the inlet section of a corresponding primary nozzle portion for subsequent ignition by the previously-formed cumulative products of `combustion being exhausted from the next-upstream positioned nozzle portion and thereby providing for the ever-increasing and thus progressively accelerating cumulative products of combustion flowing through said primary nozzle means.

2. In a modied ram jet engine as in claim 1, wherein the gas how-delivering means of said self-starter device comprises a second tube portion integrally joined with said first-named tube portion and further being shaped into a relatively small divergent nozzle section having inlet means in open communication with said first-named tube portion, said auxiliary fuel injection means being positioned immediately adjacent the said flow-delivering inlet means for intermixing an auxiliary, self-starting supply of fuel with said auxiliary supply of compressed air being exhausted thereinto from said first-named tube portion, and self-starting igniter means positioned in said self-starter divergent nozzle section further downstream therein for igniting the auxiliary, self-starter fuel-air mixture formed in said divergent nozzle section.

3. In a modified ram jet engine as in claim 2, wherein said self-starter device-divergent nozzle section terminates in an exhaust opening section positioned in overlapping relation within at least one inlet means of said primary nozzle means to thereby exhaust thereinto the products of combustion initially formed by said ignition of said auxiliary fuel-air mixture and thus begin producing thrust in said ram jet engine tube.

4. In a modified ram jet engine as in claim 1, wherein said primary nozzle means includes a series of separate, but overlapping, main divergent nozzles formed in said passageway and extending downstream to a common exhaust opening with said passageway, each of said nozzles further having an enlarged inlet opening portion arranged in overlapping relation to the exhaust end of the nextpreceding divergent nozzle, each of said divergent nozzleinlet opening portions being further enlarged and formed into increasingly-larger sizes extending in the downstream direction to respectively accommodate larger-and-larger volumes of primary fuel-air mixtures respectively induced thereinto by the successive exhaustion and flow therethrough of the products of combustion progressively formed in turn in each of said divergent nozzles.

References Cited UNITED STATES PATENTS 1,375,601 4/1921 Morize 60--264 2,663,142 12/1953 Wilson 60-39.7l 3,076,308 2/1963 Sweet 60-261 3,382,679 5/1968 Spoerlin 60L39.49

MARK M. NEWMAN, Primary Examiner D. HART, Assistant Examiner U.S. Cl. X.R. 

